Subaqueous tunnel.



IN VENTOR Patented Dec. 22, 1908. 9 SHEETS-SHEET 1I 0. HOFF.

SUBAQUEOUS TUNNEL. APPLICATION FILED APB.. zo. 190s.

O. HOFF. SUBAQUEOUS TUNNEL.

APPLICATION FILED APR. 2o. 1908.

INVENTOR WITNESSESI 0. HOFF. SUBAQUEOUS TUNNEL.

APPLIUATION FILED APR. 20, 1908.

Patented 1380.22, 1908.

9 SHEETS-SHEET 3.

INVENTOR WITNESSES:

0. HOFF.

SUBAQUEOUS TUNNEL.

APPLIOATION FILED APR. zo. 190s.

Patented Dec. 22, 1908.

9 SHEETS-SHEET 4.

Wl-rNssss:

. omg as@ 5W 0. HOFF.

SUBAQUEOUS TUNNEL.

APPLIOATION FILED APR. zo. 190s.

Patented Dec. 22, 1908.

9 SHEETS-SEEET 5.

NIIUIIIIIIIII INVENTOR wl'T'NEssss:

Wwe-nega 0. HOFF.

sUBAQUBoUs TUNNEL.

APPLIOATION FILED APB.. 20, 1908. Dec- 22 9 SHEETS-SHEET 6.

Ej. 12,. r a

WITNESSES: INVENTOR 0. HOFF.

SUBAQUEOUS TUNNEL.

APPLIOATION FILED APB. 2o, 190e.

907,35 6 Patented Dec. 22, 1908.

se( E214 5.a

0. HOFF.

SUBAQUEOUS TUNNEL.

APPLIOATIONFILBD APB. 2o, 190s,

Patented Dee.22, 1908.

9 SHEETS-SHEET 8.

INVENTO wl'ruzsses:

www 9777/71 Q 07e. Aira@ l 0. HOFF.

SUBAQUEOUS TUNNEL. APPLICATION FILED APR. 2o, 190s.

Patented Deo. 22, 1908. B SHEETS-SHEET 9.

INVENTOR WITNESSESI OLAF HOFF, OF NEW YORK, N. Y.

SUBAQU'EOUS TUNNEL.

Specification of Letters Patent.

Patented Dec. 22, 1908..

Application led April 20, 1908. Serial No. 428,013.

To all whom it 'may concm:

Be it known that I, OLAF HOFF, a citizen of the United States of America, residing vat New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Subaqueous Tunnels, ofwhich the following is a specification, reference being had therein to the ac- .com anying drawings.

T is invention relates to the construction of that class of subaqueous tunnels, which are formed by a series of preconstructed tunnel tube sections built on shore, launched and iioated to the tunnel site andv then sunk to position one after another, in a trench prepared to receive them.

My invention embodies certain improvements in the structural features of the tunnel andV in the method of carrying out the construction which is especially devised for the building of tunnels across navigable waters .where it is important to carry on the work expeditiously and by such a method as will offer the least possible temporary surface obstruction tonavigation, and will also make 1t possible to carry the tunnel to no greater depth than suffices to avoid interference with vessels passing thereover.

My construction provides a tunnel built wholly of steel and concrete and resting upon a foundation also preferably built of steel and concrete and forming part of the completed tunnel itself. Each steel tunnel tube section may be several hundred feet in length, and each tube is )rovided with ternporary bulkheads to enable it when launched, to be floated to the tunnel site.

ln sinking each section to its prepared water bed, water is gradually let lnto the tube and the sinking is controlled by air cylinders attached to the top of the section and adapted to support the weight of the tube, or nearly so, in sinking. After the section is sunk and joined to the previously laidsection, it is embedded in concrete and one of the novel features of my invention consists in so constructing the tunnel tube section that 1t serves as a form for the concrete, and in providing a continuous foundation' of concrete upon the water bed, all as more fully described hereinafter and shown in the accompanying drawings showing my invention as applied to a tunnel constructed of tunnel tube sections ofthe double or twin tube type.

Figure 1 represents an end elevation of a tunnel tubesection in osition for sinking: Fig. 2 is a longitudlna fvertical section of Fig. 1, showing the tunnel tube section as having been sunk to the water bed and illustrating the manner of connecting it to a previously laid section: Fig. 3 is a cross-section of a tunnel tube section in position upon the water bed and illustrating the method of embedding it in concrete: Fig. 4 is aY sectional side elevation of Fig. 3, and yshowing the shore end of the tunnel section: Fig. 5 is a longitudinal vertical section through one of the air cylinders used in sinking each tunnel tube section: Fig. 6 is an end elevation of one of these air cylinders, showing, in connection therewith, the means for securing it in position upon the tunnel tube section: Figs. 7,

.8, 9 and 10 represent in side and end elevations the means provided at the ends of the tube sections, for registering them with the previously laid sections and also showing in Figs. 7 and 9, in section, the joint connecting the sections: Fig. 11 is a sectional plan view of the joined ends of twin tunnel tube sections: Fig. 12 is a cross-section of the same on the line :1a-:1; of Fig. 1 1: Fig. 13 is a similar crosssection substantiallyin the plane of the joint and illustrating the method of filling lthe joint with cement: Figs. 14 and 15 illustrate in elevation and horizontal section the means by which the twin tubes of a section are united: Fig. 1,6 is a horizontal section through the means used in addition to that shown in Figs. 14 and 15 for temporarily uniting the twin tubes of each section: Fig.

17 is a plan view of the grid used in-the tunnel foundation: Fig. 18 is an end elevation of the grid, illustrating, also, the method of sinking it to position upon the water bed, the dotted lines indicating the manner in which the tunnel tube sections are intended to rest thereon after the foundation is completed: Fig. 19 is a cross-section through the trench forming the tunnel site and illustrating the method of building the foundation; and Fig. 2() is a cross-section of the completed foundation and of a tunnel tube section supported osition thereon.

he tu-nnel tube sections may be made several hundred feet in length according to the facilities for handling them and may be composed of one or more tubes 1, the drawings showing two tubes arranged, parallel with secured to the lateral edges of the diaphragms and spaced fromthe tubes thereby. The diaphragms are approximatelyof rectangular shape, being preferably cut away at the v lower corners to conform the side walls 3 more nearly to the sides of the trench, and

- they extend completely around the tubes,

the bottom forming a level base'for the support of the tubes upon the water bed. They lmay be made in one ieee but preferably are vertically divided between the tubes and secured together at their meeting edges. In this manner the tubes are set in an outer cradlelike frame which imparts great structural strength and at the same time serves as a form for embedding the tubes in concrete,the intervals between the diaphragme forming a series of separate pockets, as will appear more fully hereinafter. Half-way between eachof the diaphragms the tubes are also preferably reinforced on the inside by stiffenlng angles 5, Fig. 13, to which are removably attached radial rods 6 as shown, the ends of vthe tubes being similarly reinforced to prevent deformation in handling.

Each section of tube is provided with means at the ends for joining the sections together. rIhese means consist of a sleeve 66 secured to and forming an enlar ed socket at the end of one tube (Fi s. 7 an'fand of two rubber gaskets 7 an 8, oneseated on of the socket and' Vthe other seated in'a channel-flange 9 secured at the extreme end,of the sleeve. rIhe end of the section to be joined thereto is adapted to ent er the sleeve to the full depth of the socket, forming an annular space between it and the i, inner wall of the sleeve, and is provided with an outstanding flange 10 at a distance from flange 11 at its eXtreme end, both so arranged that they cooperate with the gaskets 7 and 8 to form two water tight joints whens'the sections are joined together, suitable bolt-holes being-provided in flanges Sli-and" 10 and gasket 8 for t e insertion of bolts 1'2lto draw the sections 'together and permanently unite them. In this manner a Water tight annular space is formed in the socket between' the twol sections are connected joints, and after the These diaphragms are4 spaced apart and inclosed between side walls v3, preferably formed of wooden sheathingl tions,

,anchor posts 34 and 35 vwardly from it, the anchor longer and serving as p' es. Ibis grid is together upon the waterbed, ythis space is filled with liquid cement, provision for filling being made in the construction of the secas will be explained more fully hereinafter. Provision is also preferably made `to bolt the sections together on the inside after access is had thereto at a later stage in the construction, by securing angle-bars 13 to the inner surface of the tubes at their ends and providing bolts 14 passing through these bars. rIhe space betweenthe angle-bars 13 may be calked if necessary.

In order to insure an absolute and exact connection between the tubes, each tubel is provided with `one or more steel pilotpins 15 and 16 A(see Figs. 7 to 10) preferably placed one on top and one at the bottom.

'lhe pilot-pins are taper pointed and are j adapted to guide the tubes into position by entering sockets in the guide lugs 17,-18 provided on the ends of the adjacent tubes. I he guide lug 17 forms a bell-shaped socket to guide the pilot-pin -15 and the latter is provided with a key Way for the insertion' ofa key 24 to hold it in engagement with the guide lug. 'I he pilot-pins are provided with eyes 19 at the points for] the attachment of cables thereto as will appear `more fully hereinafter and one or both may be detachably secured in lugs 20-21 riveted to t'he end of the tube. 'lo compensate for irre ularities in the size of the tubes, the guide ug 18 is adapted to provide fora vertical play .of its pilot-pin. Provision is also made for the attachment to the tubes of transit rods at 30 (see Fig. 12), which are detachably secured in prescribed lpositions and serve a wellknown purpose in sinking the tubes.

Before eachsection is launched, the ends of the tubes are closed with tem orary bulkheads 25, Fig. 12, to permit o' the section' being launched and towed tothe tunnel site, and suitable valves 26-27 are provided in these bulkheads for the purpose hereinafter more fully'described.

Before a section is launched, `the site for it on the water bed is prepared, commencing at the shore end of the tunnel where the laying of the sections begins, by dig ing a trench of suitablegdepth to prevent te tunnel from formin an obstruction to navigation, and upon' t e bottom of this trench a suitable foundation 31 (Fig. 20) is built for each section.

`In my construction I provide initially only for the supportkof each section at the two ends, and preferably in the middle by sinkin a grid 33 constructed of structural steel su stantially Secured to this rid and suitably distributed throughout its engtli area number of steel projecting downosts 35 being the as shown in Figs. 17 and 18.,

anchor posts 35 are driven into the ground till the Whole grid lies at the required level above the Water bed to support, at the proper height, the tube sections Which are 4 into a central and two end compartments,.

intended to lie. directly upon the grid. By means of the same scow, concrete is lthen poured through tremies 36 upon the Water bed beneath the grid and into the interstices thereof till the Whole grid is embedded Within a solid mass of concrete. Instead of concrete, the foundation may be made by filling `in with sand,. ravel, broken stone or other suitable material and When so filled in the foundation is ready for sinking the section thereupon.

When a section has been floated to the site` prepared for it, it is secured in 'ustified position by means of suitable anc or cables 38 and each tube is then equipped with tvvo air cylinders 40, see' Figs. 1 and 6, Which are supported in cradles 41 provided for them on top of the tubes and detachably and adjustably secured therein by straps 42 attached tb the diaphragms of the tubes.` The object of these air cylinders is to sustain by their buoyancy, the L.Wei ht of the tubes when submerged and filled With Water, tubes Will not be overstrained at any joint., or joints sprung during handling, causing leaks. These cylinders are proportioned according to the Weight they will be required to support in sinking, and theirbuoyancy is adjusted by means of letting Water into them or blowing Water out of them. Compressed air is used for this purpose and the cylinders are equipped with proper iiexible piping controlled by valves 43 (see Fig. 5). yEach cylinder is preferably divided by bulkheads 44 the central compartments having also a Water admission valve 45 in its underside With a valve stem extending through the top. When all is ready for sinking, Wire ropes 46 l-(Fig. 2) are fastened to the eyes in the pilotpins and passed down by divers to the end of" the tubes already sunk and concreted in.

' There the ropes are passed through the sockets in the guide lugs corresponding to the pilot-pins, thence over suitable pulleys (not shown) fastened to the tubes near the guide lugs and up through the Water to Winches on the scoW, all being so arranged that these ropes in connection With suitable lines secured to the outer 'ends of the section absolutely control its endwise movement in sinking'. 1t is obvious that other means may be applied for sinking. The-sinking .of the secso that the tion may be carried out with the aid of a single scoW 49, by rst opening the inlet valves 26 at the bottom of the bulkheads 25 in the tubes and likewise opening the corresponding air valves 27y at the top of the bulkheads. Water is thus let in and air let out, causing the tubes to sink at a speed dependent upon the inflow of the Water, and are therefore under perfect control. The air confined between the bulkheads is permitted to gradually escape through the air valves 27 near the top of the tubes, Which tubes continue to slowly sink until caught up by the air cylinders. These cylinders being adjusted, as previously described, to sustain the Weight of the submerged tubes to Within a small margin, say 10,000 pounds, at each end, the tubes are readily upheld, free to be raised or loW- ered, by means of tWo lines 48 (see Figs. 1 and 2,) from suitable derricks on the scoW 49 secured alongside. The further lowering of the section is thereby accomplished in a simple manner With the tubes evenly balanced and not overstrained at any point. Asthe tubes sink to the Water bed, the lines 46 attached to the pilot-pins are taken up and the section is landed on theprepared foundation. By pulling in on these lines the section is moved towards the one to Which it is to be joined till the tubes are in proper engagement for making the connections. A diver then secures the section from moving end- Wise out of engagement, by driving the Wedge keys 24 into the pilot-pins 15 and the tubes are brought into proper alinement by the means spoken of heretofore.

When the alinement of the section is accomplished, the diver Will insert the bolts 12 through the flanges 9 and 10, bolting them firmly together, and insert the necessary shims under the diaphragme to form an absolute even bearing at all points Where the foundation is provided. The air cylinders 40 .are next permitted to gradually fill With Water, thus causing the Weight of the tubes supported by them to be gradually transferred to the foundation and slackening the bands 42 so that they may be disconnected to release the cylinders which may then be floated to the top by expelling the Water therefrom. The same air cylinders may be lused for sinking each succeeding section.

Although the two tubes of each section are preferably connected and sunk at the same time, still if considered more expedient they may be sunk one at a time. 1f sunk in pairs, it is advisable to so connect them that one may be adjusted longitudinally With reference to the other Within a few inches of movement, to provide for any difference in their length, and this adjustment may be provided for as shown in Figs. 14 and 15 by .means of pintles 52 passing through spaced knuckles 534 secured to the diaphragms at tion and at their meeting edges, any suitable number vof .such connections being provided. The

tubes of each section are temporarily secured together-while being floated to the tunnel site and placed in position, by bolts 54 passing through the angle flanges on the meeting edges of the diaphragms, suitable spacing blocks 55 being interposed between the flanges.

When the ends of the tube sections have been bolted together as described, the joints are tested to ascertain whether they are tight, by providing the sleeve 66 of each joint, before sinking, with two flexible connections 56, as shown in Fig. 13, which connections 4lead to the scow floating above. With a force pump attached to one connecthe other closed, water is forced by the pump thrugh the annular space Within scow is anchored dation will be the sleeve, and thus the tightness of the joint readily ascertained. When the joints have been found reasonably tight, pure cement grout is then pumped into the annular space through one of the connections until it comes out through the other connection as evidence that the space is completely filled. After the joints are thus completed, the tubes are ready to be concreted in. do this bymeans of tremies in the manner shown in Figs. 3 and 4l-wherein 57 represents a s cow from which the work is done and this transversely of the sunken tubes in such a manner that its position may be readily shifted as the work progresses, spuds being provided to hold the scow against wind and waves. The scow is equipped with an efficient outfit for mixing concrete on board and delivering same when mixed to the tremies 58 which are hung from the side of the scow and deliver the concrete las requ1red, into the pockets between the diaphragms, from the bottom up. At thosepockets which are between the places where the :initialfoundation is provided, the cement will bedeposited directly upon the trench bottom, and thus a continuous cement founof the tubes.

It is obvious that one or'more pockets intermediate Nthe end supports may be wholly or partially concreted in before the air cylinders are removed in whiclr case the initial foundation in the middle may be omitted.

The advantage of the pocket construction as described, is that these pockets may be filled one at a time, thus preventing the exposure. of theconcrete to the action of the water by an extended spreadingout, and,

consequent washing away of the cement contained therein, This is particularly true where the tunnel is laid across a fast flowing stream and, further, with suitablecare in the handling of the tremies, the concrete can thus be deposited at a considerable depth by provided for the whole lengthA It is proposed'to raised to deliver the concrete thereto to the i full height of the pocket. When one pocket is filled, the scow is shifted to the nextand the tremies lowered therein.

After the depositing of the concrete, the space between the side walls and the trench sides may be lled in with sand, clay, stone or other this back surrounding conditions, or in some places the wash of the river may be relied on to lill in these spaces. As it is necessary to leave an opening in the casing or side walls ,at the ends of the tube sections to provide, access for the diver in making the connection, gates 60, (Fig. 11)', are provided to close these o enings, braces 61 being also provide to strengthen Vthecasing at these points.

In order to make the connections at the shore ends of the tunnel, a ocket is dred ed into the bank or shore and) when the tu es have been sunk and concreted in, the shore end thereof is inclosed within a coffer dam or seawall 62, as shown in Fig. 4. The pocket is then pumped out and used as a workin shaft for lining they tubes before making fina connection with approach tunnels. To ermit work on. the inner concrete lining w ere such is re uired to be commenced as soon as possible, t e bulkheads at the shore ends of the tubes and one in every other tube section should be built veryheavy and water tight so as to be capable of resisting the full water pressure. 'I he temporary bulkheads need not be as heavy. 'lhrough suitable valved apertures provided in these heavy bulkheads one section after another may be emptied of water and the bulkheads removed to give access to the section beyond. This particular construction of steel tube and the manner in which the joints between the sections are made, practically eliminates the possibility of leakage, and the general scheme of construction is such that the use of com ressed air is dispensed with, eliminating its angers and disadvantages and the 'necessity for the 'installation of an expensive plant.

While thel construction of the tunnel as herein described and shown in the drawings is primarily devised for navigable waters and has been specifically designed for the tunnel under present construction across the Def suitable material, the character of l filling depending largely upon the kso invention, to suit prevailing conditions, for instance the pockets may beiilled only partly with concrete and the rest with other material, in which case the sheathing and the diaphragms or either need generally extend up only as far as the concrete.

The advantages of my construction in cost, safety andigeneral applicability to meet the requirements, will be well understood by those skilled in the art, none of the steps in the construction involving any Adiilicult eng' eering problems and the equipmentv required being easily procurable and representing but a small portion of the cost of construction.

I do not make in this application any claims on the method involved in the construction of the tunnel herein described Aas I have made it the subject matter of a separate application iled June 1, 1908, Ser. No. 435,904.

What I claim as my invention isz 1. In a sub-a ueous tunnel, a reconstructed tunnel tiilie section compose of one or more tubes exteriorly provided at intervals with transverse diaphragmsl of substantially rectangular shape, the lower edges of the diaphra ms forming a level base adapted to sup ort t e tube at intervals upon the Wa- 'ter be 2. In a sub-a ueous tunnel, a reconstructed tunnel-tu e section com ose of one or more tubes exteriorly rovi ed at intervals with transverse diap ra ms; the intervenlng s acesbetween said y iaphragms be- 1ng close` uppn the sides and open at the top and bottom.

3. In a sub-a ueous tunnel, a reconstructed tunnel tu e section composed) of one or more tubes and an exterior frame comprising slde wa'lls and transverse partitions uniting them with the tube or tubes, the ends of the latter projecting beyond the 'ends of the frame and provided' at said ends with means for connecting them with the tubes of like sections, the side Walls leaving open gaps between .them when the sections are joined.

4. In a subaqueous tunnel, a preconstructed tunnel tube section composed of one or more tubes andan exterior frame or. cradle adapted to support the -tube or tubes in posit1on upon the waterbed land to serve as a form for embedding the same in concrete,

the frame havingjtransverse partitions dividing the form into separate pockets.

5. In a subaqueous tunnel, a preconstructed tunnel tube .section composedl of one or` more tubesand an exterior frame adapted to serve as a form for embedding the tube in `concrete upon the Water bed, the frame having transverse members dividing the form lnto separate compartments.

.6. A subaqueous tunnel com osed of one v0'1 more tubes parallel With'eac other and v approximately laid in a trench excavated upon the water bed and a body of concrete embedding the same upon the bottom of the trench, the tube y or tubes beingexteriorly provided at intervals with transverse diaphragms conforming approximately to the cross section of the trench and the concrete filling the intervening spaces between them and forming a continuous foundation below the same upon the bottom of the trench', the diaphragms forming a base for supporting the tube or tubes at intervals upon said foundation.

7. In a subaqueous tunnel, a preconstructed tunnel tube section composed of one or more tubes and an outer frame or cradle adapting the section to serve as the form for embedding the tube or tubes in concrete, the same consisting of a series of transverse diaphragms secured upon the tube or tubes and side walls secured to the edges of the diaphragms, the diaphragms being of a shape to ter ed and support the side walls in suitable relation to the tube or tubes.

8. In a subaqueous tunnel, a preconstructed tunnel tube section composed of one or more tubes and an outer frame or cradle adapting the section to serve as the form for embedding the tube or tubes into concrete, the same consisting of aseries of transverse dia hragms secured upon the' tube or tubesan 'constituting the partition walls of the form, and wooden sheathin secured to the edges of the diaphragms and forming the side Walls of the mold, the diaphragms vbeing of afshape to support the tube or tubes in position u on the water bed and support the side Wa ls in suitable relation to the tube or tubes for filling in the concrete.

9. In a subaqueous tunnel, a preconstructed tunnel tube section composed of a pair of tubes and an outer frame or cradle adapting the section to serve as a form for embedding the tubes into concrete, the same consisting vof a series of transverse diaphragms secured upon the tubes at intervals and divided in halves 'secured together at .their meeting edges and side walls secured to the diaphragms, the diaphragms being of a shape t0 support the tubes in position upon the 'Water bed and to support the side walls in proper relation to thewtubes for embedding'themv in concrete.

10. In a subaqueous tunnel, a preconstructedtunnel tube section composed of a pair of tubes and an outer frame or cradle' adapted to support the tubes in position upon the water bed and serve as a form for embedding them in concrete, the same consisting of a series of transverse diaphragms of rectangular shape secured upon the tubes at intervals and side walls secured to the lateral edges of the diaphragms support the section in positionupon vthe wa` .and constituting lthe sidesof the form the to support the tubes y, .'water bed and serve as space betweenthe sidewalls being divided l by the diaphragm into separate pockets.

11. In a subaqueous tunnel, a preconstructed tunnel tube section composed of a pair of tubes and an outer frame or cradle adapted to support the tubes in position upon the water bed and serve as a form for embedding them in concrete, the same consisting of a series of transverse diaphragms of approximately rectangular shape secured upon the tubes at intervals and side walls secured to the edges of the diaphragme, the space between the side walls being divided by the diaphragms into separate pockets open on top and bottom.

12. In a subaqueous tunnel, a preconstructed tunnel section composed of a pair of tubes and an outer frame or cradle adapted to support the tubes in position upon the water bed and serve as a form for embedding them in concrete, the same consisting of a series of transverse diaphragme secured upon the tubes at intervals and side walls secured to the ends of the diaphragms, the diaphragme being divided into halves between the tubes and means at the meeting edges of the halves for securing the tubes together lengthwise adjustable in relation to each other.

13. 'In a subaqueous tunnel, a preconstructed tunnel section tubes'and an outer frame or cradle adapted in position upon the a form for embedding 'them thereon in concrete, the same consistlng of a series of transverse artitions secured upon the tubes and side wa ls secured to the partitions, the diaphragme being of a size and shape to divide the form into separate pockyets open at top and bottom.

14. The combination of two tunnel tube sections having ends adapted to be engaged with each other, a pilot pin secured to the end of one section and a guide lug at the end .of the othervsection intowhich the pilot pin 1s adapted to engage and lglfiid'ethe tubes into alinement with each other.

15. The combination of twol tunnel tube sections having ends adapted to be engagedwith each other, a taper pointed pilot pin secured to the end of onesection, and a guide lug secured to the end of the other section and having a bell-mouthed socket to receive the pilot ping 16. The ination of two tunnel tube sections havingends adapted to be engaged with each other, two taper pointed pilot pins secured to the end ofA one of the sections at diametrically opposite-points, correspondingly secured to the ends of the other section and having guide sockets to re'- cei've the pilot pins to guide theufsections into alinement with each other.

/17. The lcombination of two tunnel tube and guide lugscomposed of a pair of ysaid ends, and a guide end and having a socket with which the guide pin is adapted to register, and means provided on the pilot pin for locking it in engagement with the guide lug. 4

18. The combination of two tunnel tube sections having ends adapted tol be engaged with each other, a pilot pin secured'to one of ug correspondingly secured to the other end and provided with a socket adapted to receive and guide the pilot pin into engagement therewith, the pilot pin eing taper pointed and provided with an eye in the point for the attachment of a line. 19. The combination of one tube section provided at one end with a sleeve forming an enlarged socket thereon, another tube section having one end adapted to enter into said socket and form an annular space between it and the sleeve, agasket supported on the bottom of the socket and adapted to form a tight joint with the end of the other tube section, another the extreme end of the s eeve, a flange on the other section adapted to cooperate with said second gasket and form a tight joint therewith and means exteriorly of the tubes for bolting the ends thereof together.

20. The combination of one tube section provided at one end with a sleeve forming an enlarged socket thereon, another tube section having one end adapted to enter into said socket and form an annular space between it and the sleeve, a gasket supported on the bottom of the socket and adapted to coperate with and forma tight joint with the end of the other tube section, said end being suitably l formed,r a channel flange around the eXtreme end of the sleeve, another gasket secured in said channel flange,

:an angle flange on the other tube section adapted to form a tight joint with the last named gasket and means for bolting the aforesaid flanges together.

21. ',Ihe combination of one tube section provided at one end with a sleeve forming an asket supported at enlarged socket thereon, another tube section adapted to be entered with one end into said sleeve and form an annular cylindrical space between it and the sleeve, means for forming a water tight joint between the sleeve and the end of the other tube section and means independent of the aforesaid means for guiding said end into the sleeve and centering it therein.

22. rIhe combination of one tube section provided at one end with a sleeve forming an enlarged socket at the end thereof,'another tube section having one end adapted toenter into and form an annular space between it and the sleeve, means for mclosingsaid space between water tight joints and means'y i at the sleeve for lling the space with liquid merged, the air caissons being provided with cement. g means for admitting Water into the same and 23. In a subaqueous tunnel, the eombinafor expelling it therefrom.

tion With a preeonstructed tunnel tube sec- In testimony whereof I affix my signature tion com rising one o1 more tubes closed in presence of tWo Witnesses.

at the en s and provided with means for ad- OLAF HOFF.

mitting Water into the same for sinking the section, of air caissons detaohably mounted Witnesses: upon the section and adapted to sustain C. R. STIOKNEY,

' and evenly balance the section when subl OTTO F. BARTHEL. 

